.Buildings.HeatTransfer.Windows.BaseClasses.ShadeConvection

Information

Model for the convective heat balance of a shade that is in the outside or the room-side of a window.

The convective heat balance is based on the model described by Wright (2008), which can be shown as a convective heat resistance model as follows:

Wright (2008) reports that if the shading layer is far enough from the window, the boundary layers associated with each surface will not interfere with each other. In this case, it is reasonable to consider each surface on an individual basis by setting the convective heat transfer coefficient shown in grey to zero, and setting the black depicted convective heat transfer coefficients to h=4 W/m² K. In the here implemented model, the grey depicted convective heat transfer coefficient is set set to h' = k   h, where 0 ≤ k ≤ 1 is a parameter.

References

• Jon L. Wright.
  Calculating Center-Glass Performance Indices of Glazing Systems with Shading Devices.
  ASHRAE Transactions, SL-08-020. 2008.

Revisions

• May 30, 2014, by Michael Wetter:
  Removed undesirable annotation Evaluate=true.
• June 11, 2013, by Michael Wetter:
  Redesigned model to separate convection from radiation, which is required for the implementation of a CFD model.
• June 27, 2013, by Michael Wetter:
  Changed model because the outflowing radiosity has been changed to be a non-negative quantity. See track issue #158.
• April 2, 2011 by Michael Wetter:
  Added homotopy operator.
• February 3, by Michael Wetter:
  Corrected bug in start value of radiosity port and in heat balance of shade.
• January 28 2011, by Michael Wetter:
  Fixed computation of convective heat balance between air, shade and glass.
• November 3 2010, by Michael Wetter:
  First implementation.